1. Field of the Invention
The present invention relates to a special effect apparatus for use in production of a television program or the like.
2. Description of the Prior Art
In television broadcasting and so forth, there is known a technique for blurring a picture either partially or entirely on a display screen by the use of a special effect apparatus, wherein a picture portion to be blurred is visually represented so that display elements of predetermined sizes (hereinafter referred to as mosaic display elements) are gathered to form the picture portion, thereby achieving a mosaic effect which represents a portion with coarse details by employing the mosaic display elements as display units.
In such a mosaic effect with coarse details, the relevant picture portion can be displayed with adequate blur to meet requirements without being represented precisely and, since the contents of the mosaic display elements are derived from the video signals of the original picture, there is the advantage that any strangeness which might be perceived in the blurred picture portion is relatively small.
One of the conventional special effect apparatus of the type mentioned is disclosed in Japanese Laid-open Patent No. 58 (1983)-14678, wherein video signals sampled intermittently are written into a memory and, when the signals are read out from the memory, the intermissions thereof are interpolated so that the same video signals are rendered continuous both horizontally and vertically at predetermined intervals to form mosaic display elements.
If the size, shape and display position of each mosaic display element can be specified in accordance with selected requirements, the mosaic effect can be utilized as one means of expression for video creation in production of a variety of television programs.
However, in the conventional special effect apparatus where intermittently sampled video signals are interpolated via a memory, it has been difficult to execute a practical dynamic change of the signal sampling interval or the timing to write or read the signals in or from the memory.